Información General

Reduction of time-to-recovery, defined by the achievement of laboratory blood marker response, confirmed at 48 hours after the initial reporting of this response

Objetivos secundarios del ensayo:

? Improvement in number of patients responding to therapy? Reduction in, plasma exchange (PE) procedure- related items ? Reduction of time to resolution or improvement of symptoms typical of TTP, including blood markers? Reduction of number of exacerbations and relapses? Improvement of cognitive level at steady state post acute phase? Improvement of clinical symptoms and organ function ? Reduction in mortality at 30 days following PE.? Reduction of concomitant treatment-related complications? Evaluation of safety and immunogenicity of adjunctive treatment with ALX-0081? Determination of pharmacokinetic (PK) and pharmacodynamic (PD) characteristics of ALX 0081 in patients with acquired TTP

1. 18 years of age or older2. Men or women willing to accept an acceptable contraceptive regimen3. Patients with clinical diagnosis of TTP4. Necessitating plasma exchange 5. Patient accessible to FU6. Obtained, signed and dated informed consent

Criterios de exclusión:

1. Platelet count greater or equal to 100,000/µL 2. Severe active infection indicated by sepsis (requirement for pressors with or without postive blood cultures)3. Clinical evidence of enteric infection with E. coli 0157 or related organism4. Anti-phospolipid syndrome5. Diagnosis of disseminated intravascular coagulation (DIC) 6. Pregnancy or breast-feeding7. Haematopoietic stem cell or bone marrow transplantation-associated thrombotic microangiopathy8. Known congenital TTP 9. Active bleeding or high risk of bleeding10. Uncontrolled arterial hypertension11. Known chronic treatment with anticoagulant treatment that can not be stopped safely, including but not limited to: - vitamin K antagonists - heparin or LMWH - non-acetyl salicylic acid non-steroidal anti-inflammatory molecules12. Severe or life threatening clinical condition other than TTP that would impair participation in the trial13. Subjects with malignancies resulting in a life expectation of less than 3 months 14. Subjects with bone marrow carcinosis15. Subjects who cannot comply with study protocol requirements and procedures. 16. Known hypersensitivity to the active substance or to excipients of the study drug17. Severe liver impairment

Criterios de valoración:

Time to response, based on the following criteria: - Recovery of platelets equal to or above 150,000/µL- This response must be confirmed at 48 hours after the initial reporting of platelet recovery equal to or above 150,000/ µL by a de novo measure of platelets equal to or above 150,000/µL and LDH equal to or less 2 X ULN